Reciprocating hand tool attachment for hand-drills



Aug. 27, 19,68 E. s. MEIER 3,398,588

RECIPROCATING HAN TOOL ATTACHMENT FOR HAND-DRILLS Filed Maren 4so, 19672 Sheets-Sheet l EMIL S. MEIER ATTORNEY -DRLLs E. S. MEIER RECIPROCATINGHAND TOOL ATTACHMENT FOR HAND Filed March 50, 1967 2 Sheets-Sheet 2ATTORNEY United States Patent O1 hee 3,398,588 Patented Aug. 27, 19683,398,588 RECIPROCATING HAND TOOL ATTACHMENT FOR HAND-DRILLS Emil S.Meier, Mountain View, Calif. (1573 Peacock Ave., Sunnyvale, Calif.94086) Filed Mar. 30, 1967, Ser. No. 626,995 Claims. (Cl. 74-50)ABSTRACT OF THE DISCLOSURE A hand-drill attachment for converting rotarymotion into reciprocating motion in 4which a reciprocating slide memberis actuated by an adjustable eccentric cam which is directly andpositively coupled to one drive shaft engageable to the hand-drill shaftand indirectly and through a friction means coupled to another driveshaft engageable to the hand-drill shaft. The reciprocating slide memberincludes clip-on means for holding sandpaper and a fastening means forholding saw blades, hammers or the like. A handle means supports thehand-drill on the attachment and provides means for convenientlyhandling the combination.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to an attachment for power tools and for converting rotarymotion to reciprocating motion and, more particularly, to areciprocating hand tool attachment for hand-drills.

Description of the prior art Many types of reciprocating hand toolattachments for hand-drills are known today as evidenced by thedisclosures of U.S. Letters Patent 2,307,174, 1,951,170, 2,282,- 728 and2,713,271, to name only a few. Each of these prior art hand-drillattachments has been found wanting in one or more respects which includesuch factors as the absence of any means to adjust the length of thereciprocating stroke, the absence of any means to change thereciprocating speed, and the absence of any means to change from adirect connection such as a gear train to an indirect connection with afriction drive, or vice versa. Further, combining the hand-drill withthe attachment produced a structure which was found wanting from thepoint of view of ruggedness and convenience in handling the same forapplying the reciprocating tool to a workpiece.

It is therefore a primary object of this invention to provide areciprocating hand tool attachment for handdrills which overcomes eachof the aforementioned deficiencies.

It is another object of this invention to provide an attachment for ahand-drill which is powered by the rotating hand-drill shaft and whicheffectively drives reciprocatingly operable hand tools.

It is still another object of this invention to provide an attachmentfor hand-drills for reciprocating a slide member to whichreciprocatingly operable tools may be attached, and which is capable ofbeing operated in at least two different reciprocating speed modes.

It is a further object of this invention to provide an attachment of thetype described having one direct or positive coupled drive, and oneindirect or friction coupled drive.

It is still a further object of this invention to provide an attachmentof the type described which includes means to securely support thehand-drill on the attachment and which also allows the resultantcombination to be conveniently handled by an operator.

CJI

It is a still further object of this invention to provide an attachmentof the type described which includes provisions for reciprocating theslide member in at least two different reciprocating speed modes, andfor continuous adjustability of the length of the reciprocating strokeover wide limits.

It is also an object of this invention to provide an attachment for ahand-drill which may be quickly and easily attached to the hand-drill,and which includes a reciprocating slide member having means forsecurely holding reciprocally operable hand tools such as saws, tiles,hammers, sandpaper and the like, and which may be operated at more thanone speed and at any desired length of stroke, and which includes afriction coupling for one speed to prevent damage to the hand-drill whenthe reciprocating tool locks to the workpiece or, in the alternative, toprevent damage to the workpiece under such circumstances.

SUMMARY OF THE INVENTION Briefly, in the preferred embodiment of thisinvention, a housing is provided to which the hand-drill may be fastenedby a handle means which also serves as a convenient handle by which thecombination of the attachment and the hand-drill may be handheld. Thehousing slidably supports a slide member to -which the variousreciprocally operable tools may be attached. The housing also includestwo rotatably mounted pulleys which are operatively connected by afriction belt and which have control shafts projecting out of thehousing for engagement with the chuck of the hand-drill. One of thepulleys carries a cam whose eccentricity is adjustable and which engagesa slot in the slide member to reciprocate the same in a direction ofmotion which is perpendicular to the pulley axis. By connecting thehand-drill to the cam carrying pulley, a direct drive is provided, andby connecting the other pulley to the hand-drill a friction drive isprovided. By making the pulleys of different diameters, a differentreciprocating speed is provided in accordance as to whether thehand-drill is connected to the larger or the smaller pulley, and byvarying the eccentricity of the cam the length of the reciprocatingstroke is varied.

Further objects and advantages of the present invention will becomeapparent to those skilled in the art to which the invention pertains asthe ensuing-description proceeds.

The features of novelty that are considered characteristic of thisinvention are set forth with particularity in the appended claims. Theorganization and method of operation of the invention itself will bestbe understood from the following description when read in connectionwith the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE l is a view of the hand-drillattachment of this invention in cross section and the handle means andhand-drill in elevation;

FIGURE 2 is a view taken along line 2-2 of FIG- URE 1;

FIGURE 3 is a view taken along line 3 3 of FIG- URE 1;

FIGURE 4 is a reduced plan View of a suitably shaped piece of sandpaperwhich may be utilized in connection with practicing the presentinvention;

FIGURE 5 is a view taken along line `5 5 of FIG- URE l; and

FIGURE 6 is a view taken along line `6 6 of FIG- URE 3.

3 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,in which like reference characters designate like parts, there is showna handdrill attachment 1G including housing 12 having a substantiallyhorizontally disposed upper surface 12a and a slide member 16horizontally slidably carried by the housing. Housing 12 has a generallyinverted U-shaped cross section comprising two downwardly disposed sideplates 12b and 12C and a top plate 12d integrally joining the sideplates. The `facing inner surfaces of side plates 12C and 12d areidentified as surfaces 12e and 12j.

Slide member 16 is of generally rectangular cross section having anupper surface 16a, a lower surface 16b and a pair of side surfaces 16a`and 16d as best seen in FIGURE 6. The lower corners of slide member 16further include a pair of horizontal and outwardly extending lips 16eand 16f which respectively overlap the end surfaces of side plates 12band 12e for sliding contact. Similarly, surfaces 12e and 16C, andsurfaces 12,7t and 16d, are in sliding contact, respectively.

There are further provided oppositely aligned V- shaped longitudinalgrooves 12g and 161 in slidingly disposed surfaces 12e and 16C, andoppositely aligned V- shaped longitudinal grooves 12h and 16j inslidingly disposed surfaces 12f and 16d which respectively formsubstantially rectangular channels. Nylon bearing rods 20a and 20h arerespectively inserted into the rectangular channels, and form aretaining bearing allowing slide 16 to slide within housing 12 in adirection parallel to its direction of elongation. Nylon bearing rods20a and 20b may be retained against motion with respect to housing 12 byretaining screws 22a and 22b which are disposed in correspondingthreaded openings in side plates 12a and 12b, respectively, and areprovided with a pointed leading edge to engage the nylon bearing rods.

Inside the rectangular space within housing 12 are a iirst pulley 30 anda second pulley 32 whose peripheral surfaces are shaped to accommodate abelt 34 which passes operatively over both pulleys. Pulley 30 has acentral drive shaft 30a which is integrally connected to pulley 30through a bearing hub 30b. Hub 30h is rotatably journalled within abearing sleeve 36 press fitted into top plate 12d and a retainer ring 38may be slipped over the end of hub 30b to retain pulley 30 against axialdisplacement.

Similarly, pulley 32 has a central drive shaft 32a which is integrallyconnected to pulley 32 through a bearing hub 32h. Hub 32h is rotatablyjournalled with a bearing sleeve 37 press fitted into top plate 12d, anda retainer ring 39 may be slipped over the end of hub B2b to retainpulley 32 against axial displacement.

Pulley 30 is further provided with a horizontally extending T-shapedslot 42 which extends part way through the pulley. A cam means 44,having its upper end portion of also a T-shaped configuration to engageslot 42, is carried by pulley 30 to extend downwardly and is positionedeccentrically with respect to the pulley axis. The lower end portion ofcam 44 is of generally cylindrical shape to engage an elongated slot 46which extends part way into slide 16 having a direction of extensionwhich is perpendicular to the direction of sliding motion. In otherwords, the direction of extension of slot 46 is perpendicular to thedirection of extension of V- shaped channels 161' and 16j.

The structure so far described is a means for converting rotary motionapplied to one of the two drive shafts 30a and 32a into reciprocatingmotion of slide 16. When rotary motion is applied to drive shaft 30a, adirect coupling to slide member 16 is provided, and when applied todrive shaft 32a, a frictional element in the form of friction belt 34 isinterposed therebetween in the coupling to slide member 16. If thediameter of pulley 32 is selected to be larger than pulley 30 as shown,it is readily seen that a friction coupling is provided for operation inthe fast reciprocatingv mode. This is as it lshould be since for sawingand filing operations, which are generally conducted at a slowreciprocating speed, a direct and positive coupling is desirable, andfor sanding and hammering operations, which are generally conducted at afast reciprocating speed, an indirect friction coupling is desirable.

It is further seen from the arrangement so far described that the throwor length of the stroke is a function of the eccentricity of cam 44 withrespect to the axis of pulley 30. For greater utility of the attachmentof this invention, cam 44 is provided with continuously variable meansin the form of a threaded bore 48 and a thrust and clamping screw 50disposed therein by which the position of cam 44 may be adjusted. Toprovide access means for clamping screw 50, an access opening 52 isprovided in slide 16 whereby a tool, such as an Allen wrench, may beinserted into the head of clamping screw 50 to loosen the same to changethe degree of eccentricity of cam 44. Clamp screw 50, when tightened,clamps against the facing portion of key slot 42 to firmly secure cam 44to pulley 30.

Referring now particularly to FIGURE l, there is also shown aconventional hand-drill 60 having a conventional Iacobs chuck 62 yforengaging either one of drive shafts 30a or 32a. Since the direction ofreciprocating motion of slide 16 of this invention is at right angles tothe axis of the rotating hand drill spindle, handle means 64 is providedwhereby an operator can conveniently grasp the combination formed byhand-drill 60 and attachment 10 for operating the reciprocating tool.Handle means 64, as best seen in FIGURE 2, includes a lower portioncomprising a pair of legs 64a and 64b adapted to engage upper surface12a to which the legs may be fastened by fastening means such as screws66 which engage corresponding threaded openings 68a, 68h or 68e and 68din top plate 12d. Openings 68a and 68h are positioned for chuckalignment with drive shaft 30a and openings 68C and 68d are positionedfor alignment with drive shaft 32a. Even though screws 66 are shown ofthe Allen head type, it is to be understood that other means offastening legs 64a and 64b to housing 12, including quick connect anddisconnect means, may Ibe employed. Handle means 64 `further includes anupper portion comprising a hand-drill engagement means in the form of aspacer member 64C whose inner surface conforms to the outer surface ofhand-drill 60 and having connected thereto the ends of a band 64d whichmay be tightened around the body of hand-drill 60 by a conventional bandtightening means 64e. It should be noted at this point that handle means64 not only provides a convenient operators grip, but also a meanswhereby a secure combination between handle-drill 60 and attachment 10is effected, More particularly, handle means 64 is clamped to hand-drill60 and includes means which are disposed and dimensioned to effect aproper coupling alignment of the hand-drill chuck with a selected pulleyshaft. Further, hand means 64 is easily engaged and disengaged byloosening -screws 66 for the purpose of shifting handdrill 60 from driveshaft 32a to drive shaft 30a and vice versa when a change ofreciprocating speed is desired. Instead of utilizing two pulleys, it isreadily understood that three or more pulleys may be advantageouslyemployed in case additional speeds are desired. These additional pulleysmay be gear connected or belt connected to the primary pulley 30.

Slide 1'6 is provided with various means to engage reciprocally operabletools. A pair of clamps 70a and 70b are fastened to opposite ends ofsurface 16a to provide a means to hold a piece of sandpaper 72 (such asshown in FIGURE 4) in place along the bottom surface of slide 16. Forbest operation, an elastic material such as foam rubber 74 may beinterposed between lower slide surface 16b and sandpaper 72. Ahorizontally extending bore 76 passing through end surface 16g of slide16 is dimensioned for engaging reciprocating tools such as illustratedsaw 78 or some other tool such as a le or a hammer. These tools may besecurely fastened to slide member 16 by mea-ns of fastening screws 80aandv80b in corresponding threaded openings extending through slidesurface 1'6b. Some tools, such as a hammer (of the general form employedin pneumatic hammers), need only be securely held in place during theworking (forward) stroke and require only a small retention force duringthe backward stroke. For such applications, the tool may be placed intocontact with end face 76a which will take the full force of the impactduring the working stroke, and a -ball 82, spring loaded in opening 76by va spring 83, may be used to engage a spherical recess in the shaftof the hammer to hold the same in place during the return stroke.

There has been described hereinabove an attachment for a hand-drill fordriving reciprocating tools in at least two selected reciprocatingspeeds. The attachment of this invention makes it possible to utilize adirect drive for slower reciprocal motion and a friction drive forfaster reciprocatory motion and for those applications where a frictiondrive is more suitable. Further, means are provided for continuouslyadjusting the length of the stroke of the reciprocating motion to suitthe particular application. Finally, handle means are provided forsecurely fastening the attachment to the hand-drill and for providing,at the same time, a convenient handle means for an operator by which thecombination may be held for operation.

While the above detailed description has shown, described and pointedout the fundamental novel features of the invention as applied tovarious embod-iments, it will be understood that various omissions andsubstitutions and changes in the form and details of the deviceillustrated may be made by those skilled in the art, without departingfrom the spirit of the invention. It is the intention, therefore, to belimited only as indicated by the scope of the following claims.

What is claimed is:

1. An attachment for hand-drills for driving reciprocatory toolscomprising:

a housing having a substantially horizontally extending upper surfaceand including a rst and second handle connection means;

rst and second pulleys rotatably mounted within said housing and havingvertically disposed central drive shafts extending through said housingfor projection above said upper surface, said first pulley including adownwardly extending cam means mounted eccentrically with respect to theaxis of its drive shaft;

a friction belt operatively connecting said first and second pulleys; n

handle means including first fastening means for en- -gaging one of saidhandle connection means and second fastening means for engaging thehand-drill,

said handle means being dimensioned such that when engaging said firsthandle connection means the chuck of the hand-drill is in axial couplingalignment with the central drive shaft of said first pulley and whenengaging said second handle connection means is in axial couplingalignment with the central drive shaft of said second pulley; and

a slide member horizontally slidably supported by said housing andincluding cam follower means engaging said cam means and tool engagementmeans for attaching a reciprocatory tool thereto.

2. An attachment in accordance with claim `1 further including meansassociated with said first pulley and said cam means for adjusting theeccentricity of said cam means.

3. An attachment in accordance with claim 1 in which said cam followermeans comprises an elongated slot in said slide member having adirection elongation substantially perpendicular to the direction ofmotion of said slide member.

4. An attachment in accordance with claim 1 in which said handle meansincludes a hand grip for hand holding the hand-drill and attachmentcombination.

5. An attachment in accordance with claim 2 in which said housingincludes a pair of spaced end facing vertical side surfaces and in whichsaid slide member includes a pair of side surfaces immediately adjacentthe side surfaces of said housing, each of said side surfaces includingan elongated groove which are vdisposed such that the groove isimmediately adjacent side surfaces to form a channel.

6. An attachment in accordance with claim 5 [further including anelongated bearing rod disposed in each of said channels.

7. An attachment in accordance with claim 2 in which said slide memberincludes a pair of clips disposed exteriorly of its lower horizontalsurface for holding sandpaper means in operative position.

y8. An :attachment in accordance with claim 2 in which said slide memberincludes a horizontal bore in its end Iface for holding the handleportion of a reciprocally operable tool.

9. An attachment in accordance with claim 8 in which a fastening meansis associated with said bore to secure the tool handle portion to saidslide member.

10. An attachment in accordance with claim 9 in which said fasteningmeans comprises a spring loaded ball.

References Cited UNITED STATES PATENTS 1,898,956 2/1933 Harvie 144--35.l2,911,843 11/ 1959 Mitchell 74-665 FRED C. MATTERN, JR., PrimaryExaminer.

W. S. RATLIFF, Assistant Examiner.

